Sealing means for a machine for centrifugally casting pipes

ABSTRACT

Sealing means for a machine for centrifugally casting pipes. The sealing means comprise a diaphragm interposed between the outer fixed case of the machine and a sleeve which is connected to the rotary mould to rotate with the latter and defines an annular space for cooling water. The diaphragm is integral with the case and with a sealing ring in rubbing contact with the sleeve and has an orifice putting the water jacket, defined by the case, sleeve and diaphragm, in communication with a pressurecompensating chamber on the other side of the diaphragm relative to the water jacket.

United States atent [1 1 Negre [451 Feb, 27, 1973 SEALING MEANS FOR A MACHINE [5 6] References Cited gggg CASTING UNITED STATES PATENTS 1,498,138 6/1924 Wld ..249 137 X [75] Inventor! Numa Paul Neg", Fume, 3,589,435 6/1971 Mhuzi n "124/297 France 3,651,859 3/1972 Wahl et al. ..164/297 [73] Asslgnee: mete Fania-es de Pom-A- Primary ExaminerJ. Spencer Overholser ousson ancy rance Assistant Examiner-John S. Brown [22] Filed: Sept. 9, 1971 Attorney-Richard C. Sughrue et al.

Sealing means for a machine for centrifugally casting g Apphcatlon Priority Data pipes. The sealing means comprise a diaphragm interposed between the outer fixed case of the machine Sept. 9, 1970 France ..7032688 and a Sleeve which is connected to the rotary mould to rotate with the latter and defines an annular space for [52] U.S. Cl. ..164/297, 164/298, 277/74 Cooling ater. The diaphragm is integral with the case and with a sealing ring in rubbing contact with the [51] Int. Cl. ..B22d 13/02 sleeve and has an orifice putting the water jacket,

' defined by the case, sleeve and diaphragm, in commu- [58] Field of Search ..164/28630l, l 14-l 18, nication with a pressure-compensating chamber on the other side of the diaphragm relative to the water jacket.

5 Claims, 2 Drawing Figures 44/ A \x g 1 2 l a 11 11 i 1 165,2: s 12 a I w 1 1Q l4 15 I WV 13 /Z: /V/////// PATENTEDFEBZYISTS $718,178

I l I l SEALING MEANS FOR A MACHINE FOR CENTRIFUGALLY CASTING PIPES The present invention relates to machines for centrifugally casting metal pipes in a metal mould or shell cooled by a water jacket, and more particularly to means for sealing the water jacket provided between a rotatable sleeve integral with and coaxial to the mould and the walls of water inlet and water outlet outer rings which are integral with the fixed case of the machine.

French Pat. No. 995,993 describes sealing means for centrifugal casting machines consisting of rubbing rings integral with diaphragms which are interposed between the sleeve and the case or between the sleeve and a water inlet or water outlet fixed outer ring. Each rubbing ring or sealing ring operates by rubbing contact with the sleeve. It undergoes wear which is all the more rapid as it is urged with high pressure against the sleeve by the pressure of the water flowing within the sleeve.

Such rubbing moreover acts as braking means which absorbs energy and requires increased power for driving the rotating part, above all as the pressure applied to the seaiing means is high.

An object of the invention is to provide sealing means for a machine for centrifugally casting metal pipes in a rotary mould or shell centered inside a sleeve defining with the mould an annular space filled with water, wherein the sealing means are improved so as to substantially reduce its pressure on the rotary sleeve and consequently the wear and braking effect.

The invention provides sealing means of the type comprising a diaphragm which is integral with the case of the machine and with a sealing ring in rubbing contact with the sleeve, the diaphragm and the ring defining a water jacket, wherein the diaphragm is provided with at least one orifice which opens onto a pressurecompensating chamber located on the other side of the diaphragm relative to the water jacket.

With this arrangement, the water pressures are balanced on each side of the apertured diaphragm since the water in the jacket communicates with the compensating chamber by way of the orifice in the diaphragm. Consequently, the sealing ring is applied against the sleeve by a force much less than in the aforementioned known arrangements having the unapertured diaphragm in which there is consequently no compensation, that is, no pressure balance on each side of the diaphragm.

According to one embodiment, the compensating chamber is defined by a second unapertured diaphragm which is secured in a fluidtight manner to the peripheral portion of the apertured diaphragm and to the sealing ring and supported by a rigid plate fixed to the peripheral edge portions of the two diaphragms.

Further features and advantages of the invention will be apparent from the ensuring description with reference to the accompanying drawing.

In the drawing FIG. 1 is a diagrammatic partial axial sectional view of a machine for centrifugally casting metal pipes comprising a plurality of sealing means according to the invention, and

FIG. 2 is a detail view on an enlarged scale of the sealing means shown in FIG. 1.

FIG. 1 shows a machine for centrifugally casting metal pipes which comprises in the known manner a carriage which is movable in translation and includes a case 1 in which is rotatably mounted a rotary centrifugal casting mould or shell 2 having an axis of rotation X--X. The mould is surrounded by a sleeve 3 which is coaxial to and connected to rotate with the mould. The sleeve 3 defines with the mould 2 an annular space or jacket 4 for a cooling water.

The mould 2 and the sleeve 3 are driven in rotation by a motor 5.

The mould-cooling water supplied by an exterior supply enters and issues from the ends of the carriage by way of pipes 6. The latter are connected to the supply, extend through the case 1 and open into two fixed annular rings 7 respectively. The rings are concentric with the sleeve 3 and mould 2 and have a U- shaped cross section. The rings 7 define two annular chambers 8 which communicate with the annular space 4 by way of two apertures 9 in the sleeve 3 in the region of the pipes 6.

The sealing means according to the invention are provided between each flange of each fixed ring 7 and the rotary sleeve 3. The machine therefore has four sealing means 1,, J J 1,. Such a machine is termed a dry case machine since the space between the case 1 and the sleeve 3 is devoid of water between the sealing means J and J the water jacket being restricted to the annular space 4 and to the chambers 8.

Each sealing means disposed between one of the flanges of the fixed ring 7 and a rubbing flange 10 integral with the rotary sleeve 3 is constructed in the following manner (FIG. 2).

The following are fixed by their peripheral edge portions on one of the flanges of the outer ring 7 a first annular diaphragm 11 provided with an orifice 12,

a second unapertured annular diaphragm 13 which is preferably thinner and more flexible than the first diaphragm and constitutes a pocket-like structure,

and a rigid annular plate 14 supporting the second diaphragm l3. 1

The inner edge portions of the two diaphragms l1 and 13 are secured to a sealing ring 15 of a low-friction material adapted to be applied in a fluidtight manner against the flange 10 of the sleeve 3.

The diaphragms 11 and 13 can be of organic synthetic material such as pure gum rubber.

The ring 15 can be of a metallic low-friction material or an organic synthetic material such as that known under the trade name Celoron.

The second diaphragm l3 defines with the first diaphragm 11 a compensating chamber 16 which is disposed on the other side of the diaphragm 11 relative to the chamber 8. The chambers 8 and 16 communicate with each other by way of the orifice 12.

The sealing means J is symmetrical to the sealing means J At the other end of the machine, the sealing means J and J, are identical to the sealing means J 1 and 1;.

The sealing means operate in the following manner When water is supplied under pressure through one of the pipes 6, it flows, for example in the direction of arrows f, in the corresponding annular chamber 8 and in the annular space 4 where it constitutes a water envelope. It issues in the direction of arrow F by way of the other annular chamber 8 and leaves the machine by way of the pipe 6 at the other end of the carriage.

In the region of each sealing means J 1,, the water flows through the orifice l2 and fills the compensating chamber 16. Owing to the rigid plate 14 supporting the second diaphragm 13, there is established in the chamber 16 a pressure equal to that prevailing in the chamber 8 so that the diaphragm 11 is in equilibrium. In other words, the pressure in the chamber 16 compensates that in the chamber 8.

The same water pressure is therefore solely exerted on the transverse face s of the sealing ring 15 which is equal to its surface of contact with the flange 10 against which the sealing ring rubs in the course of the rotation of the mould 2 and sleeve 3.

To make quite clear the novelty and improvement afforded by this arrangement, it will be recalled that in machines of known type there is only a single diaphragm such as diaphragm 11 but unapertured. There is no second diqphragm l3 and no compensating chamber 16. There is a sealing ring, such as element 15, fixed to the inner edge portion of the single diaphragm. In the known arrangement, this ring is therefore applied against the flange 10 by a force which is the product of the water pressure multiplied by the total transverse surface or area S (FIG. 2.) of contact between the water and the single diaphragm and the ring 15.

As the area s is much less than the area S, the force applying the sealing ring 15 against the flange 10 in the sealing means according to the invention is much less than that in the known arrangement. Consequently, there is reduced wear so that maintenance is restricted to the annual replacement of the sealing ring 15 whereas in the known arrangement this ring had to be replaced every 3 months. Further, the reduction in the braking effect on the mould 2 by the rubbing of each flange 10 on each ring 15 is such that the power to be furnished by the motor 5 is reduced by 15 percent.

This reduction in the braking effect on the mould 2 also permits increasing the rate of production of the cast pipes, since the mould is quicker to start rotating and the speed of rotation for centrifugally casting is more rapidly reached.

By way of modification, the invention can be applied to a centrifugal casting machine of the wet case" type, that is, the type in which the water jacket extends throughout the annular space between the mould 2 and the case 1. ln this case, two sealing means such as J l and J, are sufficient between the case 1 and the mould 2 or between the case 1 and the sleeve 3 at the ends of the machine.

Having now described my invention what I claim as new and desire to secure by Letters Patent is 1. In a machine for centrifugally casting metal pipes in a rotary mould centered inside a sleeve which defines with the mould an annular space for receiving mould cooling water and is rotatably mounted inside a case sealing means comprising a diaphragm which is integral with said case, a sealing ring in rubbing contact with said sleeve and integral with the diaphragm, the diaphragm and sleeve defining with the case a water jacket, means defining an orifice in the diaphragm,.and means defining a pressure-compensating chamber located on the opposite side of the diaphragm relative to the water jacket.

2. The sealing means claimed in claim 1, wherein the pressure-com ensating chamber is defined by a second unapertured iaphragm which 15 fixed in a fluidtight manner to the peripheral portion of the diaphragm having an orifice and to the sealing ring.

3. The sealing means claimed in claim 2, wherein the second diaphragm is in the form of a pocket and a rigid annular plate is provided which is in secured relation to peripheral portions of the two diaphragms and supports the second diaphragm.

4. The sealing means claimed in claim 2, comprising an outer ring adapted for connection to a cooling water circuit, the two diaphragms having peripheral portions secured to the outer ring.

5. A machine for centrifugally casting metal pipes, comprising a rotary mould, a sleeve coaxial with the mould and connected to rotate with the mould and defining an annular space for cooling water, a case surrounding the sleeve and coaxial with the sleeve, and sealing means located at each end of the sleeve, each sealing means comprising a diaphragm which is integral with said case, a sealing ring in rubbing contact with said sleeve and integral with the diaphragm, the diaphragm and sleeve defining with the case a water jacket, means defining an orifice in the diaphragm, and means defining a pressure-compensating chamber located on the opposite side of the diaphragm relative to the water jacket. 

1. In a machine for centrifugally casting metal pipes in a rotary mould centered inside a sleeve which defines with the mould an annular space for receiving mould cooling water and is rotatably mounted inside a case ; sealing means comprising a diaphragm which is integral with said case, a sealing ring in rubbing contact with said sleeve and integral with the diaphragm, the diaphragm and sleeve defining with the case a water jacket, means defining an orifice in the diaphragm, and means defining a pressure-compensating chamber located on the opposite side of the diaphragm relative to the water jacket.
 2. The sealing means claimed in claim 1, wherein the pressure-compensating chamber is defined by a second unapertured diaphragm which is fixed in a fluidtight manner to the peripheral portion of the diaphragm having an orifice and to the sealing ring.
 3. The sealing means claimed in claim 2, wherein the second diaphragm is in the form of a pocket and a rigid annular plate is provided which is in secured relation to peripheral portions of the two diaphragms and supports the second diaphragm.
 4. The sealing means claimed in claim 2, comprising an outer ring adapted for connection to a cooling water circuit, the two diaphragms having peripheral portions secured to the outer ring.
 5. A machine for centrifugally casting metal pipes, comprising a rotary mould, a sleeve coaxial with the mould and connected to rotate with the mould and defining an annular space for cooling water, a case surrounding the sleeve and coaxial with thE sleeve, and sealing means located at each end of the sleeve, each sealing means comprising a diaphragm which is integral with said case, a sealing ring in rubbing contact with said sleeve and integral with the diaphragm, the diaphragm and sleeve defining with the case a water jacket, means defining an orifice in the diaphragm, and means defining a pressure-compensating chamber located on the opposite side of the diaphragm relative to the water jacket. 